1. Field of the Invention
This invention relates to a time base corrector for correcting the time base error of a PAL color image signal.
2. Description of the Prior Art
A time base corrector (hereinafter sometimes referred to simply as a "TBC") as described in U.S. Pat. No. 4,258,384 is already known as means for correcting the time base error of an image signal reproduced by a video tape recorder (VTR). The disclosure of this patent is incorporated herein by reference.
Conventionally, the TBC adds a color burst signal of a reference color image signal to a color image signal whose time base error has been corrected.
The V-axis signal component of the color subcarrier signal of the PAL image signal has its phase inverted at every line. Corresponding to this phase inversion, the phase of the color burst signal alternates between +135.degree. and -135.degree. at every line. Therefore, when a color burst signal of a reference color image signal is added to a PAL color image signal whose time base error has been corrected, it is necessary to invert the polarity of the V-axis signal component of the color subcarrier signal in accordance with the phase alternation between +135.degree. and -135.degree. of the color burst signal to be added to the color burst signal of the reference color image signal. For this purpose, the TBC for the PAL system is provided with a circuit for inverting the polarity of the color subcarrier signal in such a manner that it is coincident with the phase of the color burst signal of the reference color image signal. However, incorporating such a TBC in a VTR complicates the VTR circuitry.